13 Oct
2007
13 Oct
'07
12:06 p.m.
Chuck Guzis wrote:
On 13 Oct 2007 at 7:46, dwight elvey wrote:
Funny you should mention the PPS-4: a few months ago I was working on some
reverse-engineering efforts for a PPS-4 system (actually for another list
member). He was able to provide some documents for the chips but some of the
finer timing details of the inter-chip communication are not covered (it may
be they never were covered in public documents as it could be considered
internal to the system and not relevant to the application designer). I'd like
to get back to it sometime to continue to attempt to figure it out, but in the
unlikely event anybody has gut-level specs for those chips, I'd be interested
in hearing about them.
The Osborne book doesn't cover the PPS-4 (obsolete even in 1976) but the book
was actually still helpful in that the timing of the PPS-8, which is covered in
part, has similarities.
I was interested in the task just because it was an obscure system I had never
heard of; you are but the 2nd person I've ever heard to mention the PPS-4.
After learning what I did about it I believe that two of my calculators are
based on it, that is, I've had a PPS-4 system for years but never realised it.
This was what Federico Faggin had stated at a
talk he gave at the CHM.
Packaging was expensive and they'd made volume deals on 16 pin
packages.
That's interesting, particularly considering the competition at the
time, the Rockwell PPS-4 in the funny quad-row package.
We need to be fair, though--none of these (4004, 8008, PPS-4) were
single-chip microprocessors--they all required additional support
logic chips that, it could be argued, were just as much a part of the
microprocessor as what was in the main package. The act of moving
the control and sequencing into the same package as the ALU doesn't
seem like that much of a leap in retrospect. I've even seen the
National IMP-16 referred to as a microprocessor in some documents;
that was definitely a multi-chip configuration. Something you could
simply connect a crystal and some RAM to was still in the future. One of the more humiliating memories of mine was
stopping by my
apartment with a (female) co-worker and showing her my just-assembled
new pride and joy; the MITS Altair. This would have been 1975. Her
response was something to the effect of "I thought you told me you
had a computer. THAT'S not a computer; that's a toy with blinking
lights. You paid a thousand dollars for THAT?"
What is it that H.L. Mencken said? "How little it takes to make life
unbearable: a pebble in the shoe, a cockroach in the spaghetti, a
woman's laugh." I was mortified.
I won't ask what the interpersonal outcome was, but in terms of foresight we
know who had the last laugh.